PHENOTYPIC AND GENOTYPIC ASSESSMENT OF FEATURES FACILITATING PERSISTENCE OF FOODBORNE PATHOGENS IN FOOD SYSTEMS

The goal of this project is to understand the mechanisms foodborne pathogens employ to survive in sub-optimal environments to aid in development of rational, targeted approaches to reduce the spread of these pathogens in the food supply. One of the reasons foodborne pathogens are a constant concern in both the pre- and post-harvest food production environments is their ability to survive under a variety of environmental stresses. Shiga toxin producint E. coli (STEC), Salmonella, and Listeria monocytogenes are able to survive at low pH, under high osmotic stress, and at low temperatures. Pathogen survival in the agricultural environment, on foods, and in food processing facilities is well documented. Recurring issues of foodborne pathogens in specific foods and food production environments include STEC in agricultural water systems and transfer to produce crops, STEC and Salmonella associated with low moisture foods, and L. monocytogenes persistence in food production facilities.The objectives for this project will lead to a greater understanding of the genetic basis for key phenotypes that allow foodborne pathogens to persist in the food supply chain. Each objective targets a different combination of pathogen and component of the food supply, aimed at generating data that can be used to design specific and rational solutions for controlling each pathogen.Objective 1: Identify associations between specific genetic elements and resilience phenotypes in L. monocytogenesObjective 2: Quantify entry into a dormant state for STEC exposed to unfavorable pre-harvest environmental conditionsObjective 3: Determine molecular mechanisms associated with Salmonella desiccation tolerance and long-term survival on low moisture foods